Portable heater



FIG. 1 is a top front perspective view thereof of a portable heater, showing our new design;

FIG. 2 is a left side elevation view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a front elevation view thereof; and

FIG. 8 is a rear elevational view of a second embodiment of a portable heater. 

The ornamental design for portable heater, substantially as shown and described. 